Camshaft phasers (“cam phasers”) for varying the timing of combustion valves in an internal combustion engines are well known. A first element, known generally as a sprocket element, is driven by a chain, belt, or gearing from an engine's crankshaft. A second element, known generally as a camshaft plate, is mounted to the end of an engine's camshaft.
When such cam phasers are electrically actuated, a triple shaft arrangement such as planetary gears or a harmonic drive arrangement is provided. Examples of three shafts transmissions suitable for use with a cam phaser comprise planetary gear systems, with a sun gear, planetary gears mounted on a planet carrier and a ring gear, or harmonic drive systems with a wave generator, flex-spline and circular spline.
U.S. Pat. No. 7,421,990 B2, herein incorporated by reference, discloses an eVCP comprising first and second harmonic gear drive units facing each other along a common axis of the camshaft and the phaser and connected by a common flexible spline (flexspline). The first, or input, harmonic drive unit is driven by an engine sprocket, and the second, or output, harmonic drive unit is connected to an engine camshaft.
A current tendency in the automotive industry is to optimize energy consumption in automotive vehicles.
It is a principal object of the present invention to provide an eVCP for optimization of energy consumption.